1. Field of the Invention
The present invention relates to a silicon-containing film-forming composition, a silicon-containing film, and a pattern forming method.
2. Discussion of the Background
When forming a pattern in the production of semiconductor devices or the like, microfabrication of an organic or inorganic substrate is performed using a pattern-transfer method which utilizes lithographic technology, a resist development process, and etching technology.
However, along with an increase in degree of integration of semiconductor devices provided on a circuit board, it has become difficult to accurately transfer an optical mask pattern to a resist film in an exposure step. For example, during a microfabrication process of a substrate, a dimensional error (deviation) of the resulting pattern may occur due to the effect of standing waves of light formed in the resist film. In order to reduce the effect of standing waves, an antireflection film is formed between the resist film and the surface of the substrate.
A resist pattern is also used as a mask when a substrate with a silicon oxide film, an inorganic interlayer dielectric, or the like formed thereon is processed. It is necessary to reduce the thickness of the resist film and the antireflection film along with the progress of miniaturization of patterns. Since slimming of a resist film lowers the mask performance of the resist film, there is a tendency that it is more difficult to provide a substrate with desired microfabrication without damaging it.
As a solution to this problem, a method of forming an underlayer processing film (silicon-containing film) on an oxide film or an interlayer dielectric of a substrate to be fabricated, transferring a resist pattern to the underlayer processing film, and dry-etching the oxide film or the interlayer dielectric using this underlayer processing film as a mask is used. Since the reflectance of such an underlayer processing film changes with the film thickness, it is necessary to adjust the composition and the like to minimize the reflectance according to the film thickness. Other requirements demanded of the underlayer processing film include capability of forming a rectangular resist pattern without a skirt-like foot and the like, excellent adhesion to the resist, a sufficient masking property when processing an oxide film and an interlayer dielectric, producing a minimal amount of development residue due to penetration of a resist material into the resist underlayer film, excellent resist film/resist underlayer film etching selectivity, and excellent storage stability as a solution, and the like.
In general, the resist film/resist underlayer film etching selectivity can be promoted by increasing the amount of Si atoms included in the silicon-containing film. A resin composition comprising polysiloxane using a tetraalkoxysilane has been proposed as a composition for obtaining a silicon-containing film with a large Si content (refer to Japanese Patent Application Publication (KOKAI) No. 2000-356854, Patent Application Publication No. 2002-40668, etc.).